Automatic train controlling apparatus



Oct. ll, 1932. J. P. GILLIGAN ET AL 1,881,484

AUTOMATIC TRAIN CONTROLLING APPARATUS Filed Jan. 18. 1927 2 sheets-sheet 1 www.

' 'BY 5ML @um ATTORNEYS.

Oct. 11, 1932. J. P. GILLIGAN ET AL AUTOMATIC TRAIN CONTROLLING APPARATUS Filed Jan. 18. 1927 2 Sheets-Shee ill) Patented Oct. 11V, 1932 narran STATE-s Partnr euries JAMES P. GILLIGAN AND GEORGE W'. EDVARBS, OF TOLEDO, OHIO AUTOMATIC @anni conrno'tmncr ArrAaA'rUs Application filed January 18, 1927. Serial ltd-161,908.

Our invention relates to automatic train dependent upon the energization of the solecontrolling apparatus and haste do With the provision of novelcontrol devices which cooperate with thev air brake equipment of the train and Which Will not only positively control the sto-pping of the train under conditions of extreme danger and when the block indicates stop, but Will also be` effective to stop the train When the usual trackside signal fails to indicate existing danger conditions. Tt also results in important. safety measures in that the automatic stop devices will, in normal operation, eiectually and automatically stop the train Within effective safety-limits and braking distance from any danger or block points. l

Our invention has to do primarily With the provision .of means for Ypositively releasing the air in the air brake system so as to ensure a positive stopping of the train at a safe distance from any point of danger. This stopping of the train is accomplished by means of very simple, compa-ct and positively acting structure which comprises electrically controlled means carried by the train and operated by striking a ramp, third rail, or other object Which is not charged, means for automatically charging said rail in the event that the track is safe and the train is to proceed, and solenoid control means for releasing the air brake pressure of the train Whenever the third rails are automatically de-energized or, if for any reason, there is a broken circuit leading to the third rails or Within the electrical system carried by the trainl The third rails for controlling the stopping of the train are, under normal safe conditions, connected with a current supply and such current supply is, preferably7 bro-ken only in the case oi danger to the train resulting, for instance, from the train entering an already occupied block or section.

' One of the objects of our invention is the provision of an air brake valve, cylinder and piston construction for operating such valve and solenoid operating means for normally maintaining said piston structure in inoperative position. The result is that the movement of the piston structure for opening the air brake valve to stop the train is entirely nioid whereby any deenergization of the solenoid Willpermit the actuation of the piston structure to open the valve.

A. further iobject Voit our invention is the provision of automatically operating means for controlling the stopping of the -train When going in one directionV onlyv and the provision ot' additional automatic stopping means for controlling-*the stopping of the Atrain when goingin the opposite direction.

Tn this case, when one of such devices strikes a dead third rail, the train Will be stopped. Such particular stopping device would not allectthe progress of theftrain in the `oppo-` site direction or, in other Words, When the train is going forWarch'the third rails on one side of the track control only such for- Ward movement of the' train While the third rails on the opposite side of the track control. the rearward movement of the train. Furthermore, We. have thus provided ay means whereby, When the train is positively stopped by the automatic stop device, the trainman may descend from the locomotive and adjust the air control valve and then back up his locomotive Without causing his train to be again sto ped by such particular automatic stopping device. p

A further object of our invention consists in the provision ofan air brake control valve for releasing the `air brake pressurevin the brake pipe system-and balanced lluid and solenoid control means for moving the air control valve in one direction only. Theresult is that, when the solenoid is deenergized, the fluid control means Will be effective to open the valve to stop the train, but the reenergization of the solenoid will not be effective to close the valve. Thus, the valve must be closed manually, While it may be opened automatically. p I

A still further object of our invention has to do with the provision cfa pivotedv trolley with contact closing members of unequal length on either side ot the trolley whereby, When the trolley is moved in one direction, the shorter member Will breakr the circuit carried by the train and, When the trolley member is moved in the opposite direction,

' the longer contact member will maintain the circuit, carried by the train, closed. The result is that, when the trolley member is moved in one direction by striking the third rail, the current for energizing the solenoid will either be supplied by such third rail or the solenoid core will be released to. effect stopping ot the train. However, if the trolley is moved in the opposite direction, the longer contact member will be effective to maintain the train circuit closed and to maintain the solenoid energized. Y n y Another object of our invention has to do with the provision of a switch or contactor mechanism in connection with the regular 'track switch and which is so arranged that the cont'actors for supplying current to the third rai-l will be resiliently held in position until positively moved by the track switch to non-contacting or danger indicating position. In this case, the instant the track switch is moved to a danger indicating position,the current supplied to the third railv will be immediately cut off to automatically effect stopping of the train.

Another obJect of our invention has to do with the provision of means for keeping' the -th-ird rails clean at all times, regardless ofk weather conditions, to ensure positive electrical'contact between the third rails and the trolley structure for controlling .the release of the solenoid core.

A further object of our invention has to do with the provision of a cut-out valve equipped with electrical control means whereby any one of the train stopping devices on a plurality of locomotives may be rendered inoperative. i

Many other features of our invention will be apparent as this description progresses and will be brought out in the claims appended hereto. The various objects of our invention are, preferably, obtained by the structure illustrated in the vdrawings wherein similar characters of reference designate corresponding parts and wherein Figure 1 is a diagrammatic side elevation of parts of a locomotive which is equipped with our automatic stopping mechanism also diagrammatically shown.

Figure 2 is a side elevational view of' a cut-out valve, and the switch for connecting the trolley to the solenoid to keep the solenoid constantly charged. f

Figure 3 is an enlarged detail view of the trolley structure shown in Figure 1, showing the unequal contact kmembers `carried by the trolley and the resilient mechanismy for cleaning the third rails.

Figure 4is a fragmentary horizontal cross- `section taken on line 4-4 of Figure, showing means for insulating the trolley 'member against electrical contact with theV locomotive.

Figure 5, is

a Adiagrammatic layout of thel trackside circuit as associated with a rail switch, such circuit operating in conjunction with the locomotive circuitV also diagrammatically shown.

Figure 6, is a diagrammatic layout of the trackside circuit as associated with a semaphore controlling one of the blocks along the right of way.

In the drawings, our automatic train stopping device is shown as comprising a valve 1 which controls the release of the air brake pressure in the air brake system for stopping the train. This valve 1 is obviously carried byy the locomotive but, in Figure 1, we have diagrammatically shown this valve with the air brake and electrical brake controlling mechanism of the locomotive.

As best shown in Figure 1, the air control valve is` connected to a standard air brake pipe 2 'of the locomotive. The valve is, preferably, provided with an operating cam element 3 which cam element is designed to be moved in o-nerdirection only by means of a suitable piston rod 4., which piston rod forms 'a part of the piston 5 which is, in turn, designed to reciprocate within a suitable air cylinder 6. The piston ro'd 4 is not connected with the valve cam element 3 but is merely designed to contact with one face of such cam element to move said cam element and the valve to open position to release the aid brake pressure. Y

Thepiston rod 4 is pivotally connected to one end of a lever 8 which is ulcrumed on the locomotive frame as at'9. The lower end 'of this lever 8 is preferably pivotally connected'to a rod 10 whereby any oscillation of the lever .8 Vwill be effective to move the rod 10 horizontally within its bearing supports or, in other'words, the lever 8 may be oscillated about the fulcrum) while the rods 4 and 10 connected thereto are horizontally reciprocable. The rod 10'vis connected at one end to the solenoidcore 11. This solenoid core 11 forms a part of a suitable solenoid 12.

As best shown in Figure 1, the piston 5 and cylinder Gare directly connected with the air brake pressure pipe 2 whereby the normal air bralre pressure in the pipe 2 is designed to be constantly el'lective upon the piston l5. However, in the normal operation of our device, the electric current passing thro-ugh the solenoid 12 will be effective to produce enough pull upon the'solenoid core 11 so that the tendency of the air brake pressure to move the piston v5 will be lovercome as long as the solenoid 12 is energized.

At the instant the solenoid 12 is deenergized for any cause whatever, the pulling force upon the solenoid core 11 will be obi viously released and the air brake pressure upon the piston 5 will be eiiective to move suc-h piston and'its'piston rod 4, whereby such piston rodr4, contacting only with the surface of the valve-cam 3, will move the vvalve shown in Figure 1. 'ually operated by means of the lever 3la lever to open the valve 1 and release the air pressure-in the air brake pipe 2 to stop the train. Gur device is provided with a valve 1la operated by the rod la when the valve 1 is operated. The valve 1n will release the air pressure contained in the main reservoir 60 through the pipe 2L and so obviate any possibility of recharging the brake pipe 2 as long as the valve 1a is open.

An independent brake valve 31a is also rlhis brake Avalve is manand may be used independently of the automatic brake control. y

ln Figure 1, we have shown a trolley 13 pivoted 'to' the forward part of the locomotive frame as at 14 and held in normal vertical position by the coil spring 50 (see Figure As best showninligures 1 and 3, this pivoted trolley is normally designed, when in vertical position, to act as a contact switch for connecting a contact 15 with a. contact 16. As particularly shown 'in Figure 1, the contacts 15 and 16 areseparated and theI connection between said contacts is designed to be effected by means of a contact member 17 carried by the trolley 13. lt will be noted that the contact member 17 has arms of unequal length on opposite sides of the trolley 13 and that, when such trolley 13 is in vertical position, a greater port-ion of the contact 17 overlaps the contact 16 than overlaps the contact 15. These contactsv15 and 16 are mounted upon the locomotive frame, as best shown in Figure 1, and the Contact 15 is constantly supplied with current from a suitable battery 18, carried by the locomotive, by means of a wire 19 connected to a wire i3 leading to said battery. The contact 16 is, in turn, connccted to the solenoid 12 by means of the wire 41, lt will thus be obvious that a break in the train circuit will cause the solenoid to be deenergiz-ed to subsequently permit the actuation of the-piston rod 4l.

The trolley 13 is designed to contact with a suitable third rail 20, indicated in Figure 1, and, as shown in this figure, the third rail has a relatively steep incline at the rearward end and a gradually sloping incline at the forward end. The energization of the third rail 20 is, as best shown in Figure 5, con trolicd by a suitable sempahore 21 or by means of a trackside switch 22. The electric switch in the semaphore 21 may be of any type, suiting the preference of the user.

The trackside switch 22 is provided with a contacter' rod 26 and, when the rail switch points are in closed position, this contactor rod will be operated by the movable rail points to connect the contacts 27 to cause the current to flow from the battery to a suitable third rail 20. When the rail switch points are open in dangerous position, the

'whereby vthe third rail lconnected to said ures 1 and 3. Thus, if the trolley strikes the Y third rail when the train is backing up, such trolley will be moved to the right and the eX- tended contactor will be of such length that it will serve as a connecting element between the contacts 15 and 16; therefore, when the train is moving backward the solenoid will remain energized. In order to stop a train when the engine thereof is running backwardly we provide trolley structure on the opposite side of the train that is the exact duplicate of the structure shown in Figure 1 except that the entire mechanism is reversed and is connected in series with the trolley. lstructure shown.

Therefore, the trolley structure on the opposite side of the 'locomotive will be ineffective when the train is moving forward but will be effective to disconnect the contact points when the train is moving backward.

The third rails 2O that would necessarily be placed on the opposite side of the locomotive are reversed so that the highest point is in front whereby'such third rails on the 0pposite side of the locomotive are effective to control the operation of the solenoid when the train is moving backward.

When the semaphore is at safety position or when the trackside switch is closed, the current will flow to the respective third rail 20. As the circuit on the engine is broken by the trolley 13 striking the highest point on each third rail 20, the contacter 17 will be moved away from the contact 15 and the trolley 13 will pick up the current from the charged rail, which current will flow to the solenoid by way of contact 16 and wire 41 to hold the core 11 in normal position.` However, when the trolley 13 strikes a dead third rail due to either the semaphore or trackside switch being in danger position, the contactor 17 will be moved out of contact with the contact 15 and the circuit of the solenoid will be positively broken, thus allowing the solenoid 12 to become demagnetized, releasing the core 11 and allowing the air brake pressure acting on the piston 5 to move the valve cam 3 to open the valve 1 and release the air brake pressure to stop the train. lf the trolley 13 strikes a charged third rail,

the current from the charged third rail will flow to the solenoid 12 as long as the trolley 13 is in contact with the third rail 20 but, as the train passes forward, the trolley 13 is gradually returned to normal position in passing over the sloping portion of the third rail so that Contact will be made between the contacts' 15 and 16 before the trolley 13 moves out of contact with such third rail.

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The trolley mechanism is, preferably, 'insulated against electrical contact with the locomotive frame in the manner best shown in Figur-e 4. Any preferred form of insulating material may be used to insulate the trolley pivot 14 and the spring carrier 50 but it is preferred that they beinsulated as shown at 51, 52 and 53.

The forward end of the locomotive frame is provided with a casting 28 in which reciprocates a spring pressed rod 29. The lower end of this spring pressed rod 29 is provided with a brush 30, made of some suitable non-conducting material, designed to resiliently contact with the third rail 20 just in front of the pivoted trolley 13. The object of this brush is to keep the third rail clean at all times and, thus, ensure positive electrical contact between such third rail and the trolley 13.

`A brush 24, made of some current conduct- .ing material, is supported by the casting 28 by means of a reciprocating spring pressed rod 23. The rod 23 is insulated as at 25 and the brush 24 is connected to the contact 16 by means of the wire 7. The brush 24 is placed directly behind the trolley 13 and makes a. connection between the third rail 2O and the contact 16 in case the trolley 13 is broken or fails to function properly.

In cases where it is necessary to employ a plurality of locomotives equipped with the automatic train stopping device constructed in accordance with our invention as a part of the train, such devices on any one of the locomotives may be rendered inoperative by moving the arm 34 to close the cut-out valve 31. This arm 34 also carries the contactor 38 which connects the-contacts 32 and 33 when the cut-out valve 31 is moved to closed position. By reference to Figure 1 it will be apparent that the contacts 32 and 33 are connected to the solenoid 12 and the battery 18 by thewires 43, 40 and 41 respectively, and

. that, when the cut-out valve 31 is closed and the Contact member 38 is in contact with the contacts 32 and 33, the valve 1 is held closed and the brakes are prevented from operating.

Electrical energy normally passes from the battery 25, to and through the relay 55, to the semaphore operated switch which controls the energization of the third rail and from such semaphore operated switch, to and through the relay 55, to the third rail 20. The battery -25 is connected to the main track rail byV means of the wire 56. When the semaphore operated switch is in circuit closing position current is permitted to flow to the third rail whereby such third rail is energized by current from the battery and, as a locomotive passes over the energized third yrail, the current is picked up by the trolley 13 and is transmitted to the solenoid 12 by means hereinbefore described. The solenoid 12 is grounded to the locomotive frame and the current passes from the locomotive frame to the main rail by way of the locomotive wheels. Thus, a complete circuit may be formed and the solenoid remains magnetized.

With reference to Figure 5, we have shown therein a track side'circuit associated with the ramp 20 that is designed to be interrupted to one of the rails of the main line, preferably f the one that is nega-tively charged by wire 61. ln operation, assuming that the rail points of the switch are aligned with the main line, the circuit to such ramp will be completed through wire 63, contact 27, contact bar -65 which has been moved into contact with each of the contacts 27 and 27 by the closing of the switch, wire 64 to the `ramp 20. When the trolley of the locomotive circuit intercepts the charged ramp 20, 4current will flow through either the brush 24 to the wire q41 and thence to the solenoid 12, or will pass through the trolley arm to the contact 17, through contact 16, wire 41, solenoid 12, through the ground 62 to one of the track rails, the circuit being completed bythe Wire 61 extending from the negative pole of the battery to the track rail.

l/Vith such an arrangement, it will be impossible for a locomotive to enter an open switch inasmuch as spreading of the rail points by the lever 26 automatically interrupts the circuit and deenergizes the ramp 20 which resultantly deenergizes the solenoid 12 of an approaching locomotive and effects the stopping of the train in a manner set out hereinbefore.

With reference to Figure 6, wehave shown therein a track side circuit for energizing the ramp 2O that is controlled by one of the semaphores located at intervals along the right of way. When the signal indicates a clear track in the block wherein itis located, the ramp 20 which is set in the block Vbehind is energized to prevent the deenergization of the solenoid 12 on the locomotive and the subsequent applicationof the brakes. However, should the signal indicate that the block in which it is located is occupied,the ramp 20 will be automatically deenergized and the entry of a-train 1 into such block willbe prevented.

If the semaphore is of the hand thrown type, the circuit to the ramp 20, that is operated by the semaphore 67 consists of a battery 68, lead 69, lead 71,-contact 72, contact 73, bar

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contact 74 operated by the lever 75 for throwing the semaphore blade, wire 76 connected to the ramp 20 and Wire 77 connected between the negative pole of the battery and the negatively charged track rail in the block in which the ramp 2O is located. Thus, when the semaphore indicates a clear track, the blades will be at the vertical and the circuit will be completed to the ramp 20 by reason of the contact bar 74 closing the gap between the contacts 72 and 73. Vhen the semaphore blade is moved to a horizontal position, indicative of an occupied block, the circuit is broken by movement of the contact bar 74 away from the contacts 7 2 and 73.

lf the semaphore is electrically operated and controlled by a trackside system of relays, the circuit consists of the lead 69, wire 69', lever 78 operated by relay 79, wire 86 that, for the purposes of illustration, is tapped in on the wire 76, and wire 77 leading from the battery to one of the track rails. The relay 79 is placed in series with the track side relays 80 that are a part of the standard signalling system (not shown) for electrically controlling the blades of the semaphore 67. The

relays 79 and 8O are connected across the trackv rails by means of the wire 81, and the rails are, in turn, energized by a battery 82 having a lead 83 extending to one of the rails and a lead 84 extending to the other of the rails. When the block in which the semaphore is located is unoccupied, the relay 79 is effective to close the circuit through the lever 78 and wire 86 thus energizing the ramp 20 through battery 68, wire 69, wire 69 lever 78, wire 86 and wire 76 to such ramp. f

When the block in advance of that in which the ramp 2O is located is clear, the ramp 20 will be energized in the manner just set out and the locomotive may safely pass such point without having the solenoid 12 deenergized and the brakes applied. However, on entering the block in which the semaphore is located, the lead trucks will immediately short the circuit 81 to the relays 8O and relays 79. The relays 80 will operate to allow the semaphore blade to move to a danger position, and at the same time, the switch lever 78 will be released thereby breaking the circuit through the wire 86. Thus, the block in which the semaphore is located Will be protected from the entry of a train the-reinto by reason of the deenergization of the ramp 2O located in the block therebehind.

If desired, the trackside circuit employed with the hand throw type7 of semaphore'- may be combined with the ramp controlling circuit associated with the Vsemaphore relay system and may be operated in conjunction therewith. The manner in which this may be accomplished is self-explanatory from'a study of Figure 6. In the event that the semaphore should be rendered inoperative,

'due to some failure in its mechanical makeup,

thereby putting the circuit tothe ramp out of commission, the circuit controlled by the relay Will continue to function and properly protectthe block.

Figure 7 shows a modified form of semaphole using a plurality of lights 46. The object of this modified form of semaphore is to dispense with the movable arm of the old type semaphore. In the modified form of semaphore, three lights extending vertically signifies a clear track, three lights extending upwardly at an angle signifies that the engineer is to proceed with caution and three lights extending horizontally signifies danger or stop. j

It will be obvious that we provide an automatic train stopping device which, when a, signal or the rail points of a track switch are in danger indicating position, will be eective to de-energize the corresponding third rail. rlhis third rail causes the trolley 13 to move rearwardly to break the circuit from battery 18 and thus release the air brake pressure to stop the train. Furthermore, since the automatic train stopping device is caused to operate as a result of a de-energized third rail, in the event that the current wires leading to ysuch third rail are grounded or broken the train-will be automatically stopped irrespective of the position of the trackside switch or semaphore arm.

It will further be obvious that our novel train stopping apparatus is so constructed that operative relation between the third rails 20 and the trolley structure 13 will be assured under all conditions of speed, weather, wear, oscillation and shock. The trolley 13 will always strike the'third rail 20, regardless of whether such rails are energized or de-energized and, if for any reason, the trolley 13 should stick in its oscillated position after passing the third rail, the train will be automatically stopped until the trolley is moved to its normal position to make contact between the contacts 15 and 16. It will further be apparent that the control valve 1 and the cam element 3 are pushed in one direction only by piston rod 4 and that, in order to close the valve 1 when once opened, it will be necessary for someone to manually move the valve to its closed positionk before the brakes may be released.

It will be understood that, as the operating valve 1 is normally closed, it must remain closed to permit running of the train. j

Having thus described our invention, what we claim is: ,n

1. Automatic train control apparatus comprising a third rail and electrical means for controlling the application of the train brakes embodying a trolley, a source of electrical current carried by the train,'spaced contact plates in an electrical circuit normally adapted to prevent application of the train brakes and a contact member carried on said trolley having a short arm extending to'one contact plate and a long arm extending to the other contact plate, the said contact member being effective to maintain connection between the contact plates when the trolleypasses over a third rail in one direction and to break connection between the contact plates when the trolley passes over a third rail in the opposite direct-ion.

2. Automatic train control apparatus compiising a third rail and electrical means for controlling application 'of the train brakes embodying a trolley, a source olz electrical currentl carried by rthe train, spaced Contact plates in an electrical circuit normally adapted to prevent application of the train brakes, a contact member carried on said trolley having a short armextending to one contact plate and a long arm extending to the other con-Y tact plate, the said contact member being et'- ective to maintain connection between the contact plates when the trolley passes over a third rail in one direction and to brake connection between the contact plates when the trolley passes over a third rail inthe opposite direction, a second source of electrical current independent oi" the train and means for substituting said second source of current for said source of electrical current carried by the train.

3. Automatic train control apparatus comprising electrical means for controlling the application of the train brakes embodying a trolley, a source of electrical current carried by the train, spaced contact plates in an elec-v trical circuit adapted to normally prevent ap plication 'of the train brakes, a contact member carried by said trolley having a short arm extending to one contact plate and a long arin extending to the other contact plate, the said contact member being etlective to maintain connection between the contact plates when the trolley passes over a third rail in one direction and to break connection between the contact plates when ythe trolley passes over a third rail in the opposite direction, a second source of electrical current independent of the train, a third rail section for displacing said trolley to render said first named source of current ineffective, said third rail section being effective to supply current from said second source to prevent application of the trainbrakes, andmeans for controlling the energization or de-energization of said third rail section in response to track condition.

4. Automatic train control apparatus comprising a third rail and electrical means for contr-olling the application'of the train brakes embodying a trolley, spaced contact plates in a circuit cai'ried by the train adapted` to normally prevent application of the train brakes, a contact member carriedon said trolley having a short arm extending to one contact plate and a long arm extending to the other contact plate, the Contact member being ef-k ective to maintain connection between the Contact plate. when the trolley passes over the said third rail in one direction and to break connection between the contact plates when the trolley passes over the said third rail in the opposite direction, and a non-current conducting resilient brush structure carried bythe train and contacting with the said third rail prior to the contact thereoll by .said trolley to eil'ect cleaning of the third rail.

5. -Automatic train control apparatus comprising a third rail and electrical means for controlling the application' of the train brakes embodying a trolley, spaced contact plates in a circuit carried by the train adapted to normally prevent application oi:V the train brakes, a contact member carried on said trolley having a short arm extending to one contact plate and a long arm extending to structure adapted to contact with the thirdV rail immediately after thetrolley to ensure positive connection between the third rail and the brake control mechanism carried by the train.

6. Train control apparatus comprising a brake pipe system, a main air reservoir for supplying airunder pressure to said brake pipe system, means operable by air pressure for releasing the air pressure from said brake pipe system and simultaneously releasing the air pressure from said main reservoir, and solenoid control means for normally preventing the operation of said brake pipe and main reservoir air pressure release means.

7. Train control apparatus comprising a brake pipe system, an engineers controlling valve, an air reservoir :tor supplying air under pressure to said brake pipe system, a valve `automatically, adjustable in response to certain track conditions :tor releasing air pressure in said brake pipe system independently of said controlling valve, a fluid vmotor normally under fluid pressure for operating a brake pipe system, an engineers controlling valve, an airreservoir, akpipe leading from lll) said air reservoir to said Controlling valve, a brake pipe system leading from said oontrolling Valve, a valve in said brake pipe system automatically operative in response to track conditions to exhaust air from said brake pipe system, a second Valve in communication with said pipe leading from said main air reservoir intermediate said reservoir and said controlling Valve, and means responsive to operation of said iirst named valve to simultaneously actuate said second valve.

9. Train controlling apparatus comprising a brake pipe system, an engineers controlling Valve, an air reservoir, a pipe leading f from said air reservoir to said 'controlling valve, a brake pipe system leading from said controlling Valve, a Valve in said brake pipe system automatically operative in response to track conditions to eXahust airrfrom said brake pipe system, a second Valve in Communication With said pipe leading from said main air reservoirintermediate said reser- Voir and said controlling Valve, and means responsive to operation of said first named valve to simultaneously actuate said second valve, said last named means being such that closing of said first Valve Will reposition said second valve.

In testimony whereof We hereby ahx our signatures.

JAMES P. GILLIGAN. GEORGE W. EDWARDS. 

